399 Responses to “Unforced Variations: February 2012”

Leland, you have characterized the Ruhl et.al. paper several times as proving a massive end Triassic methane release. The authors cite two other potential volcanic sources for the isotope shift that have been published previously and are only proposing a methane hypothesis that is also consistent with the isotope data. They state that “none of these mechanisms is mutually exclusive, and all three may have contributed to the release…,” and “The relative contribution of these end members for 13C-depleted carbon release is yet unknown.” They propose a possible reason why methane release might be a more likely cause, but give no discussion of mechanisms regarding why volcanic events can be ruled out.

So, you have again cherry picked a study and made inexpert and exaggerated assertions regarding what a study says. All of the scientists who work in this area will eventually reconcile the findings. You need to work on your learning curve regarding how science works. Steve

Why do you feel the need to repeat things? I am quite capable of reading, so there is no need to go over your reasoning again.

The fact remains that your estimate is substantially larger than Shakhova & Semiletov’s 1400Gt estimate. That’s before we start on my objections to their figure.

The reference you cite states “Their results show conditions are favorable for a continuous thick zone (~200 m) of stable gas hydrates in water depths up to 60m.” The ‘they’ being Romanovskii et al 2005. That paper is a thermal model based study.

In Rachold et al, 2007, “Near-shore Arctic Subsea Permafrost in Transition” PDF findings are revealed which cast doubt upon the validity of thermal modelling studies in the Laptev Sea. As part of the COAST drilling programme boreholes were drilled, Rachold et al explicitly mention Romanovskii et al. The core drilling found a substantially larger than modelled thawed region, i.e. the permafrost layer is much less than 200m. Core 2, the core taken furthest out onto the ESAS, found a frozen zone of ~30m, not 200m.

I quote:
“Considering the model data summarized above, a surprising result is that C2 encountered almost completely unfrozen sediments below a depth of 64.7 mbsl (Figure 1). This observation raises the question of whether present models hold true for subsea permafrost thickness and distribution throughout the whole Laptev Sea shelf.”

You could even be right. I’ll look into it some more. For one thing, the map shows methane hydrate potential, not methane hydrate deposits. But they use the words almost as synonyms, sometimes saying deposit, sometimes saying potential. So, the purity value could be less than 10%.

Or, it could be more than 10%.

It would be nice to know for sure, though, wouldn’t it?

If the future of the world could depend on it, why don’t we already know for sure?

Volcanic explanations require much more carbon to be released to explain the observed isotope ratio shift, seems to be their reasoning, since methane hydrates are especially enriched in C12.

Hi Chris R (# 352)

Yes, I am aware of the layer of free gas. It’s an order of magnitude estimate, and I was being conservative.

Regarding your objections, I’m not sure why you bother. If your objections are not certain enough to bet the future of the world on, then the obvious remedy to all this wrangling is to go find out how much hydrate and free gas is actually there, in some sort of open and transparent international monitoring program.

If your position is that there is enough good information about this to bet the future of the world on business as usual, I don’t think that’s true.

But we are not going up there and finding out, despite the risk to the entire world. That seems odd, to say the least.

Perhaps the trillions of dollars worth of arctic hydrocarbon resources the PNNL report talks about is warping the decision making process.

The carbon isotope ratio studies that I am aware of all talk about trillions of tons of methane release from the hydrates being necessary to explain the huge carbon isotope ratio excursions. Just about all of them, that I am aware of, use numbers greater than Archer’s estimate of 700-1200 Gtons of carbon in the methane hydrates, plus a few hundred Gtons of free methane gas. Keeping in mind that it is unlikely that the entire hydrate inventory would be depleted during these extinction events, this is a serious problem for Archer’s estimates.

Just about all the papers I am aware of neglect carbon burial during the event, and so are very conservative estimates.

So, this is not cherry picking, by any definition that I am aware of. These are huge carbon isotope excursions, and in fact the methane release explanation requires the least amount of carbon to be released to explain them.

The observed effects also argue for methane release. It seems likely that a second greenhouse gas, occupying a separate absorption band is necessary to explain the observed temperature increases and mass extinctions. CO2 alone won’t provide enough forcing, according to most experts on the matter, because of the logarithmic nature of greenhouse gas forcing, and the CO2 absorption bands getting saturated.

Oh, guessing helps a lot. Making order of magnitude estimates really is a good idea, before doing a more detailed calculation. Detailed calculations working off highly uncertain data can be wildly wrong, of course- garbage in, garbage out, no matter how fancy the computer model. That’s why serious modelers go through a whole process of making order of magnitude estimates, then doing the more detailed calculations and modeling, then running the model using information which will somehow validate it, for example using past inputs into the system and comparing the model output with the real known result. Finally, it is standard good scientific practice to see how much the predictions made by the model generally match reality.

If Dickens is right about the three low revisionist estimates of worldwide carbon as methane content of the hydrates being mostly based on computer modeling, with that modeling sensitive to assumptions, and then very little effort being made to compare those results to reality, well, that violates known good scientific practice.

About the assumption that all of the carbon must come from methane, that is the assumption which requires the least carbon, because the hydrates are the most C12 enriched source. Some could come from other sources, but it requires more carbon. The methane hydrates are also the largest and arguably the most volatile source, and large methane releases appear to be capable of stimulating further methane releases via positive feedback. For the End Triassic, there is also the associated mass extinction which fits the methane release model. Finally, to get the observed mass extinction seems to require a second major greenhouse gas other than CO2, absorbing in a second non-saturated absorption band, to provide the required forcing to fit the observed temperature increases, is my understanding.

Occam’s Razor says that there is no need to endlessly multiply hypotheses if an adequate explanation is already available.

I’ve shown you research that undermines your back of envelope calculation of 8000Gt ESAS methane, you simply ignored that. Yet again, as you seem to need reminding, your figure is far in excess of Shakhova & Semiletov’s estimate of 1400Gt, that’s before you get to my disagreements with that: In the case of these latter issues, you have been given detailed summaries of the arguments in both instances, yet you repeatedly fail to address those arguments and use the detail provided in the arguments to critically examine the 1400Gt figure and my argument that that figure is a high-end estimate. In place of dealing with evidence and detailed arguments you now cling to your 20,000Gt global figure by making guesses about the situation in the PETM.

1) Can you cite evidence to show that PETM Arctic methane inventories should be considered equal to the present?

Just about all the papers I am aware of neglect carbon burial during the event, and so are very conservative estimates.

2) Can you name these papers? – full titles, authors & year.

Regarding your objections, I’m not sure why you bother…

…If your position is that there is enough good information about this to bet the future of the world on business as usual, I don’t think that’s true.

You won’t find me supporting BAU anywhere. Whatever the problems with alternatives, BAU is not a rational option.

Why do I bother? a) For me science is about getting my mind closer to objective reality. b) I intensely dislike wishy washy arguments driven by undeclared agendas, be that from denialists or alarmists pushing scare stories not robustly supported by the evidence.

So far your arguments have been shown to be very very weak, as supported by your failure to engage with key issues. If you disagree with this you can go back to the beginning (#335) and start by:

3) Giving a detailed point by point account of why and where in their reasoning Semiletov & Shakhova’s estimate of 1400Gt is a massive under-estimate.

As for your ridiculous conspiracy theory about the amount of methane hydrate and their potential value explaining why there haven’t been more extensive drilling / seismic surveys of the amount of hydrate. It’s ridiculous because it lacks internal logical consistency: A first stage in assessing the economics of such a reserve are extensive seismic surveys followed by core drilling.

Then we’re on to Dickens, about which you claimed:

Dickens says that a previous consensus estimate before the science became distorted by politics and money to be 5 to 20 trillion tons of carbon as methane in the entire world.

What Dickens actually said was: “an appropriate range across the studies was 5000–20000 Gt (Dickens, 2001b).” However he goes on to state on page 6 that in his opinion the two best estimates give a global inventory of marine methane clathrates as 170 to 12700Gt, McGuire et al 2009 note that the Arctic Ocean and its adjacent shelves are some 5% of the global world’s ocean area, from that they continue to provide a rough estimate of Artic marine methane hydrate (their figures 2 to 65Gt). Using the same line of reasoning, and Dicken’s preferred estimates, gives 8.5 to 635Gt for the entire Arctic Ocean, of which the ESAS is but a part. For what it’s worth I’m more persuaded by S&S’s reasoning, taking into account my comments, than those low figures. But Dickens doesn’t support your excessive 8000Gt guess.

Furthermore you pretend that Dickens supports your claim that assessments of methane clathrate inventory have been reduced due to pressure from “politics and money”. Simply reading that paper shows that this is not the case. For example, Dickens is critical of Archer et al (2009) because their calculations are based on modern levels of carbon input, whereas Dickens cites research that during low sea-level stands (prevalent for the last 1M years) organic carbon input to sediment is higher than at present. The critique of Burwicz et al is similarly technical. His criticism of Milkov is summed up by this passage:

Determining the mass of the present-day gas hydrate reservoir in this way is analogous to quantifying the mass of the present-day terrestrial biosphere by estimating the area which vegetation can grow across the globe and multiplying this by the mass of plants in a few hectares from a few scattered locations.

Your claim that the fault is with modelling is baseless, Dickens’ references do not support your claim as Gornitz & Fung and Harvey & Huang, the two studies he prefers, are both model dependent studies. Any study on this issue is sensitive to assumptions.

Since it seems unlikely that all of the methane hydrates dissociated at that time, total hydrate mass, at least back then, must have been greater than that- on the order of 20,000 Gtons, at a guess.

Guessing doesn’t really help much. But the reason for this response is to ask why you assume that all carbon must have come from methane? That certainly won’t be the case with todays world.

It is a good point that you make, about the source of the forcing, and it being predominantly CO2, in today’s world.

My understanding of the methane release model is that it starts with a triggering event, a large volcanic release of CO2, for example.

So, these events start out being CO2 based, but in some cases go on to become more about methane than CO2, at their peak. They may in fact be more about atmospheric and oceanic chemistry side effects of methane release, at their peak, than they are about the methane itself. As methane hydrate stores are exhausted, and sea levels rise, the hydrate deposits stabilize due to increased pressure, and the main issue then is the secondary CO2 released. As the rock weathering cycle sequesters CO2 over thousands of years, the primary and secondary CO2 ends up being sequestered and the system returns to normal, or to some new equilibrium.

So, the methane release model also contains CO2. It is a sort of one-two-three punch, with and initial CO2 trigger (one), methane and it’s oceanic and atmospheric chemistry effects providing strong forcing (two), and the accumulated primary and secondary CO2 produced from methane oxidation locking large forcing in place for thousands of years (three).

My real concern is that there may be stages beyond two, involving ozone, nitrous oxide, and water vapor. My real concern are new absorption bands, starting out in their most potent concentration ranges, adding to forcing, and that forcing then being multiplied by the water vapor feedback.

The map I referenced shows 200,000 cubic kilometers of methane hydrate potential in the ESAS, Chris.

That would be about 200 trillion tons of hydrate, containing about 20 trillion tons of carbon, if it was all hydrate.

I really haven’t issued any estimates, Chris. I have said that according to my rough calculations, two trillion tons of carbon did not seem to be unreasonable. I said that 8 trillion did not seem unreasonable, given the uncertainties involved. Given the uncertainties involved, I’m willing to go with Shakhova’s estimates, while waiting for better information, and keeping in mind the propensity for scientists to make conservative estimates.

You think that Shakhova’s estimates are too high. OK, fine, if you think that the process you are going through of reading and comparing results between papers will help you find the right number, well, go for it. I doubt it personally, and suspect that some of the information has been warped by the non-scientific factors involved, so I consider it unlikely that all your efforts will arrive at the correct number.

But I don’t have the time, or the energy, to jump through all of your hoops.

There is a wide range of uncertainty on all of these calculations. Estimates for total hydrate mass vary by orders of magnitude.

There may be better information sources, which I haven’t located yet. I’m certain that the oil corporations have better information, for example.

I can provide you with a list of papers which calculate large hydrate releases during past events (not just the PETM) in the trillions of tons of carbon range, but it will take me some time to compile such a list. I’ve referenced several of them, so far.

According to the “gas hydrate dissociation” hypothesis
(Dickens et al. 1995), some Earth system threshold was
crossed, so that deep ocean temperatures rose rapidly. This
warmth propagated into sediment on continental slopes,
which shoaled the base of the GHSZ and converted large
amounts of gas hydrate to free gas. Nominally 2000–
3000 Gt C, as free CH4 gas, then escaped from marine sediment through slumping or venting (Dickens, 2003).

Here, we present compound-specific carbon-isotope data of long-chain n-alkanes derived from waxes of land plants, showing a ~8.5 per mil negative excursion, coincident with the extinction interval. These data indicate strong carbon-13 depletion of the end-Triassic atmosphere, within only 10,000 to 20,000 years. The magnitude and rate of this carbon-cycle disruption can be explained by the injection of at least ~12 × 10E3 gigatons of isotopically depleted carbon as methane into the atmosphere. Concurrent vegetation changes reflect strong warming and an enhanced hydrological cycle. Hence, end-Triassic events are robustly linked to methane-derived massive carbon release and associated climate change.

Our analyses support the idea that both the Early Toarcian and Early Aptian isotopic curves were indicative of large episodic methane releases (5000 and 3000 Gt respectively) promoting warm ‘greenhouse’ conditions in the Mesozoic

Compare this to David Archer’s figure of 0.7 to 1.2 trillion tons methane plus a few hundred billion tons of free methane gas.

OK, here’s another one, Hesselbo et al (2000), talking about 1.5 to 2.7 trillion metric tons of carbon released during an oceanic anoxic event from methane hydrates. They also say that if synchronous burial of light organic carbon is taken into account, the mass of methane derived carbon necessary to cause the carbon isotope excursion is very much greater:

The mass of methane-hydrate carbon necessary to cause the negative excursion over this short timescale can be estimated using simple mass-balance equations7. Taking present-day mass and d13C estimates, we calculate that 1.5 × 10E18 to 2.7 × 10E18 g of carbon is required for excursions of −2 or −3.5‰ respectively. These ﬁgures are 14–24% of the estimated present-day gas-hydrate reservoir (compare 14–19% for the LPTM using estimates of reservoir mass and isotopic composition derived from refs 7 and 24). If the synchronous burial of light organic carbon is taken into account, the mass of methane-derived carbon necessary to produce the excursion is very much larger

Do we really think that these probable hydrate dissociation events released all of the hydrate, and reduced the methane hydrate stability zone to zero volume? Do we really think that all the trapped associated methane gas bubbled out of the sediments? Some deep hydrates and associated free gas must have been left after these events, so the global hydrate inventory during these events must have been greater than the amount released during those events.

All of this makes the modern revisionist estimates of total worldwide gas hydrate inventory look less and less likely. We are coming out of a series of ice ages and low water periods, with increased carbon burial in sediments and low water temperatures, all of which should make current methane hydrate inventories greater than in the past, not smaller, is my understanding. Please correct this if I am wrong about this point. Should methane hydrate accumulations now be less than in the past, and if so, why?

The Ruhl et al. paper does not support your contentions. It is a hypothesis that requires confirmation. This, and comments of others demonstrate that your ability to accurately read and report on this area of research is untrustworthy.

OK, here’s Dickens arguing that the series of progressively smaller warming events following the PETM are strong evidence of a carbon capacitor in the form of methane hydrate deposits, progressively storing and then suddenly releasing carbon in response to orbital forcing, but becoming weaker each time:

There is also a growing appreciation that the PETM is only the most prominent of a series of “hyperthermal” events that occurred during long-term deep-ocean warming of the early Paleogene (Lourens et al., 2005; Nicolo et al., 2007; Agnini et al., 2009; Stap et al., 2009, 2010; Leon Rodriguez and Dickens, 2010; Zachos et al., 2010). At least ﬁve other events, presently called ETM2/H1, H2, I1, I2, and K/X (following Cramer et al., 2003), have been identiﬁed in multiple records and follow the PETM at approximately 53.7, 53.6, 53.3, 53.2, and 52.5 Ma. Like the PETM, these events display evidence for Earth surface warming (including in the deep sea) and massive injection of 13C-depleted carbon to the ocean and atmosphere; more interestingly, with available data, they appear coupled to orbital forcing and to have a relationship between magnitude and time (above references). Speciﬁcally, there seems to be a decrease in the magnitude of the δ13C excursion with a shorter duration since the previous event (i.e. PETM> ETM2/H1 > K/X > I1 > H2 ∼ I2). Assuming the PETM and the other events have a similar generic cause, their characteristics almost demand inclusion of some large capacitor in the global carbon cycle that can release 13C-depleted carbon fast in response to forcing, but that recharges more slowly (Dickens, 2000, 2003; Nicolo et al.,2007; Zachos et al., 2010; Westerhold et al., 2011).

This is a straightforward prediction of the methane release theory, but difficult to explain by any other means I am aware of.

It’s a good theory.

It makes good quantitative predictions.

It predicts we are in great danger- especially if the methane hydrate inventory is larger than Archer, Milkov, and Burwicz say it is.

Rhul et al calculate 12 trillion tons of carbon release from methane hyrates…into the atmosphere, during the End Triassic.

Not into the oceans and atmosphere, but into the atmosphere only.

But much of the methane released today from the hydrates will go into the oceans directly, and be directly oxidized into CO2, in the oceans, then directly deposited as carbonate sediments, without ever making it into the atmosphere. Some of the carbon from the methane released would make it back out of the oceans, as evolved CO2, but not all of it.

Rhul’s calculations are based on waxes from land plants.

So, if 12 trillion tons of carbon from methane made it into the atmosphere, how much carbon total was released into both the atmosphere and oceans?

How much carbon was left over in the deep stable hydrates or in trapped free gas which never escaped?

Suppose 9 trillion tons of carbon went directly into the atmosphere. Suppose 6 trillion tons of carbon released as methane went directly into the oceans. Suppose half of that, or 3 trillion tons made it back into the atmosphere, from the oceans, equaling Rhul’s 12 trillion tons. That would leave 3 trillion tons going directly into carbonate sediments, for a total of 15 trillion tons of carbon as methane released.

Suppose as much methane was retained as deep stable hydrates and free trapped methane gas as was released into both the atmosphere and oceans.

That would bring the total methane hydrate and free gas inventory up to about 30 trillion tons of carbon content, in line with the high end estimates of worldwide hydrate mass, not the low end ones.

This could all be wrong. Maybe as the oceans acidified, carbonate sediments would themselves be dissolved, and become a source of atmospheric carbon. Or, in an ocean release scenario, much of the carbon released could stay in the oceans and never make it into the atmosphere.

My message when posting here has always been that methane release is a highly uncertain situation, and not to be taken lightly or ignored. We just don’t know what will happen if large amounts of methane start to be released from the hydrates. We certainly don’t want to bet the future of the world on this sort of complicated situation, full of positive feedback loops and combined physical, chemical, and biological effects.

And we urgently need to know how much methane and hydrate are in ocean sediments, and its distribution, especially as regards to depth. We cannot allow this information to be proprietary.

The Ruhl et al. paper does not support your contentions. It is a hypothesis that requires confirmation. This, and comments of others demonstrate that your ability to accurately read and report on this area of research is untrustworthy.

RECAPTCHA says ridiculum rosacti. Rosacti is a real insult. Steve

Yes, Steve, all of paleoclimatology and a good part of geology are based on hypothetical scenarios aimed at explaining current geological evidence. Including Ruhl et al.

We find that under plausible temperature and pressure conditions, the abundance of gas hydrates would be similar or higher in the Palaeogene than at present.

Don’t just fixate on the ‘similar’, they also say ‘higher’. Nobody knows, either is feasible. As I’ve had to tell more denialists than I care to remember: The door of uncertainty swings both ways.

According to Dickens a 4degC warming of the seafloor over 10k years would result in a 50% reduction of the stability zone. This implies something approaching 50% of the gas hydrate being reduced to get an idea of total inventory. So you can at least double any emission amount. Then, back to Dickens, there is the issue of the other hypotheses. Let’s immediately drop the comet – there’s no evidence of an impact crater. But peat burning seems a reasonable outcome of the PETM and there is also evidence of vulcanism having a role, Dickens accepts these factors as a likely partial precursor to the PETM carbon cycle feedback. For what it’s worth, so do I. Yet you seem to be exclusively concentrating on hydrates – they were not the only player in the PETM.

Frankly I’m getting bored of this, still don’t see your 20000Gt as supported in the literature, and don’t get your obsession with Dr Archer’s estimates.

I second Steve’s comment regarding Ruhl, furthermore the landmasses were radically different then, so trying to support estimates of methane hydrate now using emissions then is daft – same with your other cases, both in the Mesozoic.

Note that Ruhl et al state:

None of these mechanisms is mutually exclusive, and all three may have contributed to the release of 13C-depleted carbon at the ETME, with thermogenic methane and gaseous CO2 release from CAMP initiating a positive feedback in the global exogenic carbon cycle, causing the release of methane from clathrates. The relative contribution of these end members for 13C-depleted carbon release is yet unknown.

..

…However, given the duration and magnitude of the observed end-Triassic negative CIE, a strong contribution from the methane-clathrate reservoir may be likely.

As none of us are experts in the field we’re best to take the expert’s views. I’m happy to take Dickens as an expert.

Dickens prefers two studies which give a range of 170 to 12,700Gt methane, this being so wide that it covers Archer & Milkov, also a substantial part of the range of Burwicz. So if we take Dicken’s preferred range then that covers all bases. Where our bases are based on peer-reviewed science, not back of envelope reasoning.

The magnitude and rate of this carbon-cycle disruption can be explained by the injection of at least ~12 × 10E3 gigatons of isotopically depleted carbon as methane into the atmosphere.

They seem to be presenting this as their lead hypothesis, Steve. As always, alternate explanations to methane release from the hydrates are possible, but require more carbon, and so are considered less likely by most people.

That’s good information, from Dickens, on the total quantity of hydrates, I think. So, as I suspected, there is no particular reason to think that today’s hydrate mass is an order of magnitude less than it has been in the past. Could be more, could be less, but should be in the same ballpark.

Now do you want to move this discussion on?

No, not particularly.

Can you think of a more important or urgent topic to discuss?

Why should we move this discussion on? It’s been an interesting discussion so far, and it’s given me a lot to think about- your paper from Dickens, for exmaple, which I was not aware of.

What’s more important than a possible or even probable methane catastrophe in our future and perhaps in our very near future?

See your post #318, you first raised the Dickens paper on this thread, I last read it in November and didn’t bring it up.

What’s more important than a possible or even probable methane catastrophe in our future and perhaps in our very near future?

Er.. The more robustly supported risk of drought linked to the observed skew in the frequency of occurence of warm events. Or the likelihood of the Arctic becoming seasonally sea-ice free as early as the 2020s. Or the fact that so far as a civilisation we’re doing diddly squat to deal with our idiotic addiction to fossil fuels.

I believe in dealing with high probability imminent threats to worrying about speculative distant ones.

Actually, it’s about average if you include the high end estimates, Chris.

Note that Ruhl et al state:

None of these mechanisms is mutually exclusive, and all three may have contributed to the release of 13C-depleted carbon at the ETME, with thermogenic methane and gaseous CO2 release from CAMP initiating a positive feedback in the global exogenic carbon cycle, causing the release of methane from clathrates. The relative contribution of these end members for 13C-depleted carbon release is yet unknown…

…However, given the duration and magnitude of the observed end-Triassic negative CIE, a strong contribution from the methane-clathrate reservoir may be likely.

Yes, some mix of hydrate and alternate explanations are possible, but require more total carbon to be released, and so are considered less likely by most people. So, to completely replace the methane with peat would require ~5 trillion tons of peat, as opposed to ~2 trillion tons of methane, for the PETM, for example.

I think I focus on the hydrates because that appears to be where the biggest threat to our existence and the biosphere lies.

If the methane release theory is correct, then emergency action to stop use of fossil fuels using alternative energy sources would be justified. We would also need to put carbon back underground, for example by combining biomass energy with carbon capture and storage.

Er.. The more robustly supported risk of drought linked to the observed skew in the frequency of occurence of warm events. Or the likelihood of the Arctic becoming seasonally sea-ice free as early as the 2020s. Or the fact that so far as a civilisation we’re doing diddly squat to deal with our idiotic addiction to fossil fuels.

I believe in dealing with high probability imminent threats to worrying about speculative distant ones.

Interesting collection of conceptual frames…all based on the idea that climate change will be gradual, and mostly limited to increases in CO2, as advocated by Archer.

I don’t think it will be gradual, Chris. I expect to see horrendous, probably irreversible, and likely unstoppable effects in my lifetime- and I’m an old guy. I expect to see substantially accelerated and probably unstoppable releases from the methane hydrates in the Arctic and the ESAS, in the next few years, as Shakhova warns. I think the natural processes of methane release are already being accelerated, and will ramp up quickly from here, via positive feedback.

I think it likely that Archer, Milkov, and Burwicz are an order of magnitude low on their estimates of total hydrate mass. If those estimates give us a false sense of security, and affect policy decisions, those decisions could kill the biosphere.

Methane hydrate is a form of water ice, Chris.

Does ice melt, in response to increasing temperature?

How certain can we be that we can predict the rate at which it will melt, including wild card factors like underwater landslides?

Are we certain enough about our hydrate models to feel confident we have included all potential side effects and accelerating factors?

The existing modeling in fact gives very ominous results, especially for the shallow water hydrates like the East Siberian Arctic Shelf.

Suppose we wait for publicly available proof of massive coming methane releases before we act decisively, and by then it ends up being too late?

Re ‘Dickens’ – I’d refer to that paper on early Palaeogene hydrates as “Gu et al”, because Guangsheng Gu is the lead author, hence the confusion.

Yes ice melts – the dissociation of methane hydrate is an endothermic process – i.e. needs input of heat to progress. The big question is; how fast? Crucially the heat needs time to proceed through the layers of sediment.

I remain unconvinced by the 50GT figure of Shakhova & Semiletov (S&S). But even if it’s a lower figure then how could there be a near synchronous release across the whole of the ESAS? How would a rapid release in one area teleconnect to a talik/fault hundreds of km away? There are the results of Dmitreno et al. Their study suggests that what is being observed in the ESAS is a result of the inundation of the ESAS during the early Holocene, with recent Arctic warming playing a small role. I’ve read nothing that chalenges that interpretation, so in short; we do not know if what S&S are observing on the ESAS is the start of some massive and imminent release, or if it’s a process that has been going on for millenia. Even if we assume that this is a process that’s recent, then how likely is it that many Gt are poised to go at the same time (i.e. within a decade)?

Then we have the issue of landslides and pockmarks. Both are likely to be a factor, indeed I have stated that I do not expect a steady rate of emissions from the marine hydrates – the process is likely to result in background emissions with pulses due to landslides and pockmarks. However, how catastrophic will these be? Both are self limiting processes; landslides are limited by the geography of the seafloor, pockmarks are observed to be limited to no more than the order of 1km maximum (whilst they could be the resut of rapid events they clearly come to a natural end after initiation). Pockmarks at Blake Ridge are estimated to have emitted up to 1Gt of methane maximum. Using Dr Archer’s model, such a pulse would cause a virtually undetectable radiative forcing, a short-lived uptick in atmospheric concentration, and a minor increase in methane lifetime. A long way from a catastrophe.

Yes, AGW will cause more emissions from the ESAS, however these emissions are likely to be chronic. The biggest Arctic player now is northern wetlands, even S&S agree that emissions from the ESAS aren’t a major player at present. Both isotopes and AIRS support this.

Positive feedback? You say you expect to see “substantially accelerated and probably unstoppable releases” in the next few years. At what level would these need to be to be to constitute a positive feedback? I’d suggest at least something approaching the order of 0.3Gt per year sustained, which would match current net anthropogenic forcing. That’s an increase of Arctic methane emissions of around 3 to 10 times, within the next few years? As for ‘horrendous’ – you’re really back to S&S’s 50Gt or something in that ballpark, You are aware of my criticism of that figure, before we get to the issue of how likely it is that it would all go within a timescale of the order of a decade. That’s the sort of timescale needed to replicate S&S’s “~12-times increase of modern atmospheric methane burden with consequent catastrophic greenhouse warming.” e.g. Shakhova et al “Predicted Methane Emission on the East Siberian Shelf.” figures 2, 3, & assoc text.

Yes, I understand that you are motivated by fear, an underlying motivation has been apparent throughout these discussions. However what chance do you think you have arguing for pre-emptive action when the threat of imminent, massive and catastrophic release is unproven? How will you undo the damage if it doesn’t happen and people arguing for your position are held up as examples of yet more AGW activists crying wolf?

Positive feedback? You say you expect to see “substantially accelerated and probably unstoppable releases” in the next few years. At what level would these need to be to be to constitute a positive feedback? I’d suggest at least something approaching the order of 0.3Gt per year sustained, which would match current net anthropogenic forcing. That’s an increase of Arctic methane emissions of around 3 to 10 times, within the next few years?

Looking at the NASA maps of temperature anomalies, Chris, the biggest temperature anomaly on the planet is parked right over the East Siberian Arctic Shelf.

It may be possible for chronic plumes of methane to cause local temperature anomalies, and for the high methane concentration directly over those plumes to create local positive feedback greenhouse forcing. I certainly don’t want to bet the future of the planet against this, or on someone’s computer model- especially in a world full of non-scientific factors including power, influence, and profit.

Yes, I understand that you are motivated by fear, an underlying motivation has been apparent throughout these discussions. However what chance do you think you have arguing for pre-emptive action when the threat of imminent, massive and catastrophic release is unproven? How will you undo the damage if it doesn’t happen and people arguing for your position are held up as examples of yet more AGW activists crying wolf?

Are you aware how closely your arguments follow standard climate change denier protocols? Accusing people alarmed over global warming of being afraid is standard Denier technique, Chris. I expected more from you, and am very much disappointed.

In my laboratory experience, I provide data, and that data is used to keep projects we work on in control. If wrong decisions are made on the basis of that data, the projects can spiral out of control, and fail.

The only way to bring the climate system back into control, in my opinion, is start with a big injection of scientific truth, and then devise appropriate remedial action based on that truth.

I have no fear of “crying wolf”, Chris. I am afraid of not “crying wolf” when there is in fact a real wolf.

That anomaly is due to open water causing warming, not methane. Don’t guess, your guesses will probably be wrong, read the research.

I seem like a denialist? Your performance here speaks volumes – choosing one extreme side of the uncertainty (repeated), failing to properly read your sources (e.g. #360 re Dickens), choosing what elements of the evidence you deal with (e.g. #343 para 2, #360 para 1). Scientific truth involves assessing all the evidence, you seem to me to have developed rather a pattern of walking away from issues you don’t want to deal with.

You may have no fear of crying wolf, because you genuinely believe there is a wolf. But what matters here? The objective reality or your beliefs? Anyway I don’t think you have made a very strong case that we face imminent, massive and catastrophic methane releases. Earlier in reference to my posts on this matter you said: “So, when I saw your stuff, I admit that I took a quick look at it, and dismissed it as unlikely.” If I seem verbose you should bear in mind that what I have written is a slimmed version of the original draft, I couldn’t truncate the matter any further because it is complex. Having read some 30+ papers on the subject since last Autumn I can assure you of one thing: ‘a quick look’ is insufficient to grasp the complexity of this matter.

I mentioned fear because it is quite apparent from your final sentences post 377. Personally I’m always concerned that I may be wrong, that makes me put what real scientists say ahead of my conclusions.

Once again, I am scared by some issues, don’t believe me? Read this. I just need coherent robust evidence to be persuaded.

Have you read the RC archives about the Bryden results? More here. When Bryden’s initial results were first published they were touted by some as meaning the THC was about to shut down, more research and a longer time-series led to the understanding that the THC is more variable than thought at the time, and no, it’s not shutting down. I’m sure I don’t need to explain the relevance.

Maybe one reason I have no fear of crying “wolf”, Chris, is that I have seen past estimates of the pace of global warming exceeded time after time. We’re seeing effects on the Arctic sea ice that senior scientists are characterizing as thirty years ahead of schedule.

For example:

Climate models had projected the passage would eventually open as warming temperatures melted the Arctic sea ice—but no one had predicted it would happen this soon.

“We’re probably 30 years ahead of schedule in terms of the loss of the Arctic sea ice,” said Mark Serreze, a senior scientist at the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado.

“We’re on this fast track of change.”

So one reason I suspect that the future will not be gradual is that climate change has not been gradual, so far.

We were told that the Antarctic ice caps were stable, but Peter Ward says that they have destabilized suddenly in the past- I’m still trying to track down his references for this. More later on that.

Methane concentrations are rising rapidly, with most of the methane so far coming from terrestrial sources, that is true. But we were talking about the future, Chris.

Perhaps you are right. Perhaps it is the permafrost decay which will cause the sea ice to retreat, and this in turn will set off the hydrates. We are lucky that hydrate dissociation is endothermic. But the heat content of the oceans is definitely rising, and that heat will inevitably dissociate the hydrates. Once again, the question of the total hydrate mass seems crucial- “chronic” releases from a huge mass of hydrate could have catastrophic effects.

I seem like a denialist?

No, not really. But accusing people who are alarmed about global warming of being afraid is standard denialist technique, Chris, and is not a worthy argument. Since you ask, you seem to be more like a guy who wants to occupy the center of the argument- then shift that center to the gradualist point of view.

Leland, most of the readers here are as aware as you of the problem.
You’re looking at part of the problem pretty far into the disaster we’re hoping to avoid. Most of us are looking at the earlier stages of the disaster.

You know how it is with accidents — the big mistakes are often made minutes or even hours before the metal starts crumpling.

Methane is like that.

You’re in a crowd of people who are saying “don’t go in that direction because there are a whole lot of bad things along that path” .

You’re jumping up and down yelling “at the end of that path something really bad happens”

Somehow you think nobody but you knows the end of the path is bad, because the rest of the people are saying that every damn step in that direction along that path is bad and the farther you go the worse it gets.

You’re demeaning and ignoring real warnings and somehow trying to say you’re the only one who knows there’s a problem.

This is what Joe Romm meant a while back about the discussion being preempted by the denialists and the alarmists who won’t let anyone hold a conversation without shouting their position over and over, preempting any other discussion.

We know it’s bad. We know it gets worse. We know the end of the path is extremely ugly. We get it.

You’re saying “don’t end up there.”

We’re saying “don’t go in that direction, it’s bad all along.”

As a doctor friend of mine used to tell patients:

“If you don’t change, you’re going to end up where you’re headed.”
——-

When a car has crashed, you can say
— oh, big mistake knitting when the airbag popped open
— oh, big mistake hitting that tree
— oh, big mistake running off the road
— oh, big mistake driving while sleepy

You’re focusing on the passenger who should avoid holding knitting needles when the airbag pops open.

The scientists are warning about the loose nut behind the steering wheel that’s going to cause a lot of damage eventually.

“If given the chance to talk to an expert on global warming, the Alarmed and Concerned would most like to know what the nations of the world can do to reduce global warming, and if there’s still time to do so. The Disengaged would most like to ask whether global warming is actually occurring, and what harm it will cause. The Cautious, Doubtful and Dismissive would most like to have an expert explain how scientists know that global warming is happening and is caused by human activities.”http://thinkprogress.org/romm/2011/09/10/316193/if-you-could-ask-a-climate-science-one-question/

Leland,
The area where you are expressing your concern is an area of active research. It is science. There are lots of papers being published, and the papers disagree wrt their conclusions. That’s the fun part–science on the cutting edge.
Unfortunately, it means that the threat you are trumpeting is not firmly established–certainly not to the degree you are asserting. It will take a decade or more, probably, before it is firmly established. At that time, it will become the subject of risk analysis, mitigation, etc.

So what can we do while we wait for the science to catch up to you? We can try to address the firmly established threats that are driving the threat you say is going to wipe us out.

…accusing people who are alarmed about global warming of being afraid is standard denialist technique…

????
Theres no shame in feeling fear. If aspects of AGW don’t scare a person then they simply don’t get it. My whole argument is that it’s only by looking at the detail of the science that we can get to grips with what should scare us and what we needn’t actually lose sleep over.

Perhaps it is the permafrost decay which will cause the sea ice to retreat, and this in turn will set off the hydrates.

I disagree, regardless of methane, which is currently a small player, without _massive_ cuts in CO2 emissions the Arctic _will_ transition to a seasonally sea-ice free state. Indeed I think we’ve already passed the ‘tipping point’ which Nghiem’s findings using QuikScat have revealed – the massive and precipitous loss of perennial sea-ice culminating last decade. We are now living with a new Arctic ice-pack, one that is predominantly first year sea-ice. Events like 2007, and possibly spring 2010 (I’m looking into that at present), I see as being epiphenomenal of the loss of multi-year ice. The ice-pack has lost it’s stabiliser and is now far more responsive to weather impacts. I’d put good money on virtually sea ice free summers (under 1M km^2) by the 2020s. In Winter 2009/10, and what I see as a summer pattern since 2007, we’re now seeing the wider atmospheric impacts of the loss of sea-ice, just a taste of what we’ll see next decade.

you seem to be more like a guy who wants to occupy the center of the argument

Firstly the position I take on issues is arrived at by reading the science. That’s how I dealt with my former scepticism of AGW, and it’s a policy I find works. Secondly, I used to be a free-market Conservative voter, I’ve lost my politics because it doesn’t offer solutions to the problems we face (AGW/Population/Fossil Fuel Depletion), so I no longer do positions. I’m aware that I can annoy both sides of the argument over AGW, that is irrelevant, evidence and reason is what counts.

PS – my main obsession is the Arctic, telling me about what’s going on there is like taking coals to Newcastle. ;)

Please can someone help me? I am working through Dr. Archer’s Climate 101, trying to solve the Stefan Boltzmann equation for the “bare rock” temperature on the moon’s surface. I’m using “Microsoft Mathematics” to help me. I’ve taken the following steps, to solve for T:

But is there an elephant sitting in the living room which we are not talking about?

For example, the total mass of methane hydrates- which is very likely the most important number in science? This number could after all determine the difference between a survivable methane catastrophe and one that could kill the biosphere.

Here’s the situation we have now:

The total mass of carbon stored as CH4 in present-day marine gas hydrates has been estimated numerous times using different approaches as reviewed in several papers (Dickens, 2001b; Milkov, 2004; Archer, 2007). Prior to 2001, several estimates converged on 10 000 Gt, and this “consensus mass”(Kvenvolden, 1993) was often cited in the literature. However, the convergence of estimates was fortuitous because different authors arrived at nearly the same mass but with widely varying assumptions; an appropriate range across the studies was 5000–20 000 Gt (Dickens, 2001b). In the last ten years, estimates have ranged from 500-2500 Gt (Milkov,2004), ∼700–1200 Gt (Archer et al., 2009), and 4–995 Gt (Burwicz et al., 2011) to 74 400 Gt (Klauda and Sandler, 2005). The latter is almost assuredly too high (Archer, 2007). The others are probably too low

The three low range estimates don’t make any sense, if the methane release theory of mass extinctions is correct. According to the hard isotope ratio measurements, much larger amounts than that have come out of several mass extinction events, as I’ve mentioned. Also such events would reasonably have left some hydrate behind- perhaps doubling the total methane hydrate mass. Also, some of the methane would have likely been oxidized in the oceans and would never have made it into the atmosphere, being deposited as carbonate instead- further increasing the total hydrate mass.

The methane release theory has the most explanatory power, the most predictive ability, and the greatest amount of supporting evidence. It alone appears to be a true generic explanation for most mass extinction events.

It’s been about 50 million years since the PETM and a series of smaller hyperthermal events discharged the methane capacitor. Presumably hydrates have been accumulating since then. In the past several million years, there have also been ice ages and low water temperatures which expands the gas hydrate stability zones.

So, potentially, the clathrate gun is cocked and loaded and ready to blow our brains our.

Since we’re all so concerned, how about a unanimous vote of approval for determining the total mass of methane hydrates precisely?

Leland. As I write this there have been 18 posts since my last reply to you and 9 (exactly half) are yours. They are all way too long and, in fact, continue to consist of the Hokey Pokey dance of your inexpert opinion about real science (hand waving to physicists).

I just checked the question you’re talking about. Your math is correct but the question asks “what is the equilibrium temperature of the surface of the moon, on the equator, at local noon, when the sun is directly overhead, in Kelvins?”

This is not what you are calculating. You are looking at the traditional radiative balance equation that assumes that the temperature is essentially uniform over the entire planetary sphere. You could also think of it as saying that L(1-a)/4 is the local solar radiation over every point on the sphere, uniformly. This assumption works good on Earth where atmospheric and ocean circulation transport heat around, such that the deviation in temperature over the globe (in Kelvins) is relatively small, often to within 10% or so.

But on a body like Mercury, the Moon, or perhaps some tide-locked exoplanet with no heat transport, it is a rather useless equation, since the day-side/night-side or even the temperature over latitude can deviate by hundreds of degrees Kelvin. In the case where you only want to treat the local solar radiation at noon, at the equator, think what term you might want to change in that balance equation.

There is a rather clear mode change in 2007. The anomalous summer melt pattern has now persisted for 5 years. There is, of course, also a gradual decline from start of the data series in 1979, possibly accelerating.

after the Queensland and NSW biblical floods of 2010 and 2011,
75% of NSW is being flooded or on flood watch again today.
My son on the QLD sunshine coast has a property that has never flooded going back over 80 years, his house is twelve metres above the little creek running through the property. he woke up saturday morning to find 10mm of water in the house after a 340mm downpour in just three hours.